Wind turbine with auxiliary unit

Abstract

The wind turbine includes a tower, a nacelle mounted on the tower, and a rotor for harvesting wind energy by rotation of the rotor about a rotor axis extending in a vertical central plane. The nacelle includes a main unit and two auxiliary units housing first and second working parts, respectively. To obtain a combination of part reuse and good weight distribution, the first working parts in the first and second auxiliary units have the same distance to the central plane, and the second working parts in the first and second auxiliary units have different distances to the central plane.

Description

[Technical field]

[0001] The present disclosure relates to a wind turbine including a tower, a nacelle mounted to the tower, and a rotor for harvesting wind energy by rotation of the rotor about a rotor axis. The nacelle includes a rotor support assembly that provides a load path from the rotor to the tower, and a body bearing that is mounted to the rotor support assembly and supports rotation of the rotor relative to the rotor support assembly. [Background technology]

[0002] Wind turbines increase in size, both in terms of nominal power output and in terms of the physical dimensions of the individual components of the wind turbine. Thus, the size of the nacelle must also increase to accommodate the necessary wind turbine components. Wind turbines are typically transported by road, rail, ship, or a combination of these from the manufacturing site of the individual components to the operating site where the wind turbine is installed. Summary of the Invention

[0003] It is an objective of embodiments of the present disclosure to promote greater modularity, ease of design and manufacture, and improve assembly operations of a wind turbine. It is a further objective of embodiments of the present disclosure to provide a nacelle that is transportable using common transportation means, reducing transportation and handling costs without limiting the possible size of the nacelle, and allowing a good balance between weight distribution and modularity.

[0004] In accordance with these and other objects, the present disclosure provides in a first aspect a wind turbine including a tower, a nacelle mounted to the tower, and a rotor for harvesting wind energy by rotation of the rotor about a rotor axis extending in a vertical central plane, the nacelle including a body unit housing a rotor support assembly forming a load path from the rotor to the tower. The body unit rotates about a yaw axis extending in a vertical transverse plane. The vertical transverse plane is perpendicular to the vertical central plane. The nacelle further includes a first auxiliary unit mounted to the body unit on a first side of the central plane and a second auxiliary unit mounted to the body unit on a second side of the central plane. The second side is opposite the first side with respect to the central plane.

[0005] Each of the first and second auxiliary units houses first and second operating parts, the first operating parts of the first and second auxiliary units having the same distance from the central plane, and the second operating parts of the first and second auxiliary units having different distances from the central plane.

[0006] The different distances to the central plane allow one part of the auxiliary unit, i.e. the auxiliary unit including the second operating part, to be mass-produced in a common configuration without having to consider its subsequent positioning on the right or left side of the main unit, and allow another part, i.e. the first operating part, to be mounted in the most advantageous way in terms of weight distribution. Thus, the present disclosure provides a balance between, on the one hand, reusing identical parts and thus facilitating mass production, and, on the other hand, allowing the selected parts to be well adapted to load distribution.

[0007] Examples of main units and / or auxiliary units include units of any size and shape that are configured to be assembled.

[0008] The auxiliary units and / or the main unit can be formed with a size and / or outer shape that matches or is equivalent to the size and shape of a shipping cargo container, so that each unit inherits the advantages of the shipping cargo container with respect to handling, transportation and storage. The shipping cargo container can be handled anywhere in the world, for example by ship, train, truck, etc., and has a low cost compared to bulk transportation.

[0009] The cost savings are even more pronounced when the main unit and / or auxiliary units are shipping freight containers. Shipping freight containers, also known as intermodal shipping containers, standard freight containers, box containers, ocean freight containers, or ISO containers, generally refer to containers used to store and move materials and products in the global containerized intermodal freight transportation system for intercontinental traffic. Shipping freight containers may follow the dimensional and construction specifications for Series 1 freight containers in the ISO standard ISO668:2013.

[0010] The main unit and auxiliary units may be arranged side by side, separated by a center plane in a direction away from the axis of rotation defined by the rotor support assembly, rather than being staggered in the direction of the axis of rotation.

[0011] Each of the two auxiliary units may have the size of half a shipping freight container according to the dimensional and construction specifications for series 1 freight containers of the ISO standard ISO 668:2013, and the two halves of the container may be assembled to form one container during transportation, and may be split into two auxiliary units, for example, to be placed on either side of the main unit. The container may in particular be split into a connection extending in the longitudinal direction of the container, i.e. the longest dimension of the container.

[0012] The nacelle may be carried directly by the tower or indirectly by the tower via an intermediate tower structure. If the wind turbine is of the conventional horizontal axis type, the nacelle is typically carried by a yaw arrangement between the tower top and the nacelle. However, the present disclosure may also be relevant to multi-rotor wind turbines of the type in which two or more nacelles are carried by a transverse beam structure which is again carried by the tower via a yaw arrangement between the tower and a transverse beam structure.

[0013] The present disclosure may relate to upwind or downwind wind turbines.

[0014] The body unit is the part that connects the nacelle to the tower either directly or indirectly via said intermediate tower structure or structures. The body unit may in particular be the central part of the nacelle and houses parts of the driveline such as at least a part of the rotor shaft.

[0015] The wind turbine may be a direct-coupled wind turbine, with the generator typically located outside the nacelle, or the wind turbine may be one with the generator located within the body unit, which supports the rotor via a rotor shaft.

[0016] The body unit includes a body frame forming part of a rotor support assembly that forms a load path from the rotor to the tower, e.g., via said intermediate tower structure and, e.g., via said yaw arrangement. The body frame may in particular be a cast part.

[0017] The main unit may further include various components for power generation, hydraulic controls, computers, and the like.

[0018] In addition to the body frame, the rotor support assembly may include bearing structures and other components that support the rotor in the wind turbine.

[0019] The first and second auxiliary units have substantially the same dimensions, the first operating part is arranged in a mirror position with respect to the central plane, and the second operating part is arranged in substantially the same position within each auxiliary unit.

[0020] The first working part may be mounted directly to the rotor support assembly and define a load path extending directly from the first working part through the rotor support assembly to the tower. In particular, the first working part may be mounted directly to the body frame of the rotor support assembly and thus carried entirely thereby. To this end, the wind turbine may include an assembly structure that removably connects the first working part to the body frame, for example by use of bolts or the like.

[0021] The second working part may be indirectly mounted to the rotor support assembly via an auxiliary unit housing the second working part. In one example, the second working part is supported on, for example, a floor or wall of the auxiliary unit. The indirect mounting thereby defines a load path from the second working part through the auxiliary unit to the rotor support assembly and from the rotor support assembly to the tower.

[0022] The first working part is located at the center of gravity (herein referred to as 1 st -COG) can be attached to the rotor support assembly so that it is located exactly in the transverse plane or at a distance from the transverse plane that is less than the radial dimension of the tower, particularly the radial dimension of the tower at the point where the tower meets the nacelle.

[0023] The auxiliary unit may have a center of gravity (referred to herein as AU-COG), where the distance of the AU-COG from the rotor is 1 st -COG is longer than the distance to the AU-COG, which means that, taking into account the wind direction, st - Means it is behind the COG.

[0024] The auxiliary unit may have both a first and a second longitudinal auxiliary wall extending parallel to the central plane, in which the first and second actuating parts are located between the first and second longitudinal auxiliary walls, which extend along the outer surface of the main unit.

[0025] The body unit may also define first and second longitudinal body walls extending parallel to the central plane on either side of the rotor support assembly, and the first longitudinal body wall may extend along an outer surface of the first longitudinal auxiliary wall of one auxiliary unit and the second longitudinal body wall may extend along an outer surface of the first longitudinal auxiliary wall of the other auxiliary unit.

[0026] The first actuating parts of the first and second auxiliary units can be arranged on the first longitudinal auxiliary wall, for example directly against a surface of the wall.

[0027] The second actuating part of one auxiliary unit can for example be arranged on the first longitudinal auxiliary wall and the second actuating part of the other auxiliary unit can be arranged on the second longitudinal auxiliary wall.

[0028] The first working part may be carried directly by the body frame and further attached to the first longitudinal auxiliary wall.

[0029] The second operating part of one of the first and second auxiliary units is attached to a second longitudinal auxiliary wall of that auxiliary unit, or the second operating part can be carried by a floor of that auxiliary unit.

[0030] The first and second longitudinal auxiliary walls may be joined by third and fourth transverse auxiliary walls extending parallel to the transverse plane on either side of the first and second working parts, for example defining a rectangular box-shaped auxiliary unit. The third transverse auxiliary wall is defined herein as a wall that is closer to the rotor than the fourth transverse auxiliary wall. The second working part may be arranged at the same distance to the fourth transverse auxiliary wall and / or the first working part may be arranged at the same distance to the fourth transverse auxiliary wall.

[0031] The first operating part may in particular be a heavier operating part than the second operating part and may be the heaviest operating part arranged on the auxiliary unit.

[0032] The first and second working parts may in particular form part of a power conversion assembly, in particular for converting electrical power, for example for adaptation to a power grid, or for converting electrical power into other forms of energy, for example chemically bound energy.

[0033] One of the first and second working components may be a transformer, a converter, a battery, or a fuel cell. In one embodiment, the first working component is a transformer and the second working component is a converter.

[0034] The main unit may include busbars forming first and second conductor structures. One conductor structure may be connected to the second working part of one auxiliary unit, and the other conductor structure may be connected to the second working part of the other auxiliary unit. The conductor structures of the main unit may be arranged in a mirror position with respect to the central plane. They may extend, for example, from a generator arranged to extend to the rotor shaft and the power transmission device.

[0035] The auxiliary unit may include an auxiliary conductor structure arranged to connect to one of the first and second conductor structures, the auxiliary conductor structure in the first auxiliary unit may be different from the auxiliary conductor structure in the second auxiliary unit, thereby corresponding to a right or left position of the auxiliary unit on the main unit.

[0036] Each of the first and second auxiliary units may include a connection structure for connecting the first working part. The connection structure may include a conductor arrangement in a mirror position with respect to the central plane.

[0037] In a second aspect, the present disclosure provides a method for manufacturing a wind turbine according to the first aspect.

[0038] This method is - manufacturing first and second auxiliary units at a first location; - mounting a second working part within the first and second auxiliary units while the first and second auxiliary units are at the first manufacturing location; - transporting the first and second auxiliary units to a second location; and - inserting a first working part into the first and second auxiliary units while the first and second auxiliary units are at a second manufacturing location; - mounting a first working part to a rotor support assembly; Includes.

[0039] The step of inserting the first operating part into the first and second auxiliary units can be performed after the step of attaching the first and second auxiliary units to the main unit, and the step of inserting the first operating part into the first and second auxiliary units can be performed before the step of attaching the first and second auxiliary units to the main unit.

[0040] The method according to the second aspect may include any step implicit to the wind turbine according to the first aspect. [Brief description of the drawings]

[0041] [Figure 1a] FIG. 1 shows a wind turbine having a nacelle mounted to a tower. [Figure 1b] FIG. 1 shows a wind turbine having a nacelle mounted to a tower. [Figure 1c] FIG. 1 shows a wind turbine having a nacelle mounted to a tower. [Diagram 2] FIG. 1 shows a nacelle including a main unit and two auxiliary units. [Diagram 3] FIG. [Figure 4] A diagram showing the nacelle from above. [Diagram 5] FIG. 2 illustrates a portion of the rotor support assembly, i.e., the body frame, formed as a single cast piece. [Figure 6] FIG. 2 illustrates a portion of the rotor support assembly, i.e., the body frame, formed as a single cast piece. [Figure 7] FIG. 1 shows details regarding the centres of gravity of different parts. [Figure 8] 11A-11C show different connections between the working parts and the body frame. [Figure 9] 11A-11C show different connections between the working parts and the body frame. [Figure 10] 11A-11C show different connections between the working parts and the body frame. [Figure 11] FIG. 13 is a diagram showing that the main unit and the auxiliary unit are separate units. [Figure 12] 11A to 11C are diagrams showing different connections between the main unit and the auxiliary unit. [Figure 13] 11A to 11C are diagrams showing different connections between the main unit and the auxiliary unit. [Figure 14] 11A to 11C are diagrams showing different connections between the main unit and the auxiliary unit. [Figure 15] 11A to 11C are diagrams showing different connections between the main unit and the auxiliary unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] This detailed description and the specific examples, while indicating embodiments, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure will become apparent to those skilled in the art from this detailed description.

[0043] Figures 1a and 1b show a wind turbine 1 with a nacelle 2 mounted on a tower 3. A hub 4 carrying three blades 5 forms the rotor and is carried by a rotor support assembly in the nacelle 2. Typically the rotor support assembly includes a gear train and a rotor shaft connecting the generator to the hub. However, gears are not necessarily required as the generator may be driven directly by the rotor shaft. Figure 1b shows a direct-coupled wind turbine where the generator 6 is located outside the nacelle. The rotor support assembly further includes a body frame and a body bearing in a body bearing housing connected to the body frame.

[0044] As defined herein, the rotor rotates about a rotor axis 7 that extends in a vertical central plane 8. To orient the rotor into the wind, the nacelle 2 is rotatable about a vertical yaw axis 9. A vertical transverse plane 10 extends across the nacelle through the yaw axis 9. The transverse plane 10 is perpendicular to the central plane. The yaw axis 9 extends in both the transverse plane 10 and the central plane 8.

[0045] Figure 1c shows the centre and cross sections of the nacelle as seen from above. The tower is indicated by circle 11 and has a radial dimension indicated by arrow 12. The radial dimension shown is the dimension of the tower at the point where the nacelle is attached to the tower, circle 11 is dimensioned only to show the location of the tower. The actual dimensions of the tower relative to the dimensions of the nacelle may differ from the illustration.

[0046] Figure 2 shows a nacelle including a body unit 20 and two auxiliary units 21, 22 housing the main working components. Dividing the nacelle into a body unit and an auxiliary unit provides advantages in terms of manufacturing and assembly as well as transportation, as will be further explained below. A cooling area 23 is located at the top of the nacelle. The cooling area is formed by a heat exchanger which may form part of the body unit and / or the auxiliary units. The nacelle, and in particular its body unit 20, is mounted to the tower 3 via a rotor support assembly and a yaw arrangement (not shown). The yaw assembly allows the nacelle 2 to rotate about a yaw axis to point the rotor into the wind.

[0047] Figure 3 shows a perspective view of the nacelle 2 of Figure 2. In Figure 3, for purposes of illustration, the outer wall of the nacelle 2 is made transparent, thereby allowing the internal components of the nacelle 2 and the wind turbine components housed therein to be seen. The body unit 20 houses a rotor support assembly that supports the rotor. The rotor support assembly includes, among other things, a body frame and a body bearing 31 attached to the body frame to facilitate rotation of the rotor.

[0048] The disclosed wind turbine further comprises a gear train 32 and a generator 33 arranged in sequence behind the hub 4 along a direction defined by the axis of rotation of the hub 4. The components within the body unit mainly form part of the drive train. In another embodiment the generator is arranged outside the nacelle as shown in Figure 1b.

[0049] The auxiliary units 21, 22 house a converter unit 34 and a transformer unit 35, which here constitute two different working parts carried by the main unit, although housed in the auxiliary units. In another embodiment, the working parts may be electrolytic cell stacks or batteries etc. The auxiliary units are attached to the main unit on either side of the central plane.

[0050] The auxiliary units include similarly functioning operating components, ie, both of the auxiliary units include, for example, a transformer and a converter, or both of them include a battery, etc.

[0051] The converter units 35 are not arranged symmetrically with respect to the central plane, but rather they have different distances to the central plane.

[0052] Figure 4 shows the nacelle 2 from above. The main unit 20 includes the rotor support assembly 40, and the auxiliary units 21, 22 include the converter 34 and the transformer 35. Figure 4 shows that the first working part, in this case the transformer unit 34, is arranged symmetrically with respect to the central plane. This means that the transformer is arranged at the same distance to the central plane. The second working part, in this case the converter, is arranged asymmetrically with respect to the central plane, i.e. at a different distance to the central plane. This allows mass production of auxiliary units that are substantially identical in terms of arrangement and associated conductors in units with the second working part pre-mounted.

[0053] The rotor support assembly 40 includes assembly structures 41, 42 to which the first working part is attached directly, for example to a body frame, to the rotor support assembly. The body frame of the rotor support assembly is fixed to the tower via a yaw assembly that allows rotation about a yaw axis. The rotor support assembly thereby defines a load path that extends directly from the first working part through the rotor support assembly to the tower.

[0054] The second working component is indirectly attached to the rotor support assembly via the auxiliary unit, for example, attached to a floor or wall of the auxiliary unit, which is attached to the main unit, the auxiliary unit and the main unit thereby defining a load path from the second working component through the auxiliary unit to the rotor support assembly and tower.

[0055] The first working part (the transformer in this example) is significantly heavier than the second working part (the converter in this example), and therefore this heavier part is suitable for placement in the auxiliary unit even later in the manufacturing process, for example after the auxiliary unit is attached to the main unit or after the nacelle is attached to the top of the tower. At this point in the manufacturing process, the auxiliary unit is defined as the right or left auxiliary unit, and the first working part can be precisely positioned and directly carried by the rotor support assembly, in particular by the main frame of the rotor support assembly. A transformer for a 10 MW turbine may weigh 16 tons or more, compared to a converter weighing, for example, 12 tons.

[0056] Figure 5 shows an embodiment of the body frame formed as a single cast part. In this embodiment, the assembly structure 41 is bolted directly to the cast part and forms the suspension of the first working part directly to the rotor support assembly. The body frame forms a flange 50 for mounting the body bearing housing.

[0057] FIG. 6 shows a single cast rotor support assembly provided with assembly structures 41, 42 on either side, facilitating the direct connection of the first working parts of both auxiliary units to the rotor support assembly, in particular to the body frame of the rotor support assembly.

[0058] FIG. 7 shows a single cast body frame in the nacelle of FIG. 4. The first working part is st - The rotor support assembly is attached at the center of gravity of the first working part, indicated by COG. st -COG is 1 mm from the cross section. st -The tower is located near the cross section 10 so that the distance to the COG is less than the radial dimension 12 indicated by the dotted line 77 of the tower indicated by the circle 11. st -Note that the relative size of the tower to the rotor support assembly is not necessarily accurate as it is illustrated only to illustrate the location of the COG.

[0059] The auxiliary unit has a center of gravity indicated in the drawings by AU-COG. The distance from the rotor to the AU-COG is 1 st -Longer than the distance to the COG.

[0060] Both auxiliary units define first and second longitudinal auxiliary walls 70, 71 extending parallel to the central plane 8 on either side of the first and second working parts.

[0061] The first longitudinal auxiliary wall 70 of the auxiliary unit extends along the outer surface of the main unit. Figure 7 shows that the first operating part is arranged, for example, directly against the first wall. The second operating part of one auxiliary unit 21 is arranged, for example, directly against the first wall 70, and the second operating part of the other auxiliary unit 22 is arranged, for example, directly against the second longitudinal auxiliary wall 71.

[0062] The body units define first and second longitudinal body walls 72, 73 extending parallel to the centre plane on either side of the rotor support assembly. The first longitudinal body wall 72 extends along the outer surface of the first longitudinal auxiliary wall 70 of one auxiliary unit and the second longitudinal body wall 73 extends along the outer surface of the first longitudinal auxiliary wall 70 of the other auxiliary unit.

[0063] The second operating component is wired by a conductor structure 74. The conductors 74 extend from a generator 78 in the main unit to the second operating component in the auxiliary unit.

[0064] In the main unit, the conductors 74 of the conductor structure to the first and second auxiliary units extend symmetrically with respect to the central plane 8. In the first and second auxiliary units, the second operating parts are located in the same position, but the conductors of the conductor structure are arranged differently to provide connections to the left and right sides of the main unit, respectively.

[0065] The first and second longitudinal auxiliary walls are joined by third and fourth transverse auxiliary walls 75, 76 which extend parallel to the transverse plane 10 on either side of the first and second working parts. The third transverse auxiliary wall 75 is closer to the rotor than the fourth transverse auxiliary wall.

[0066] The first operating part is arranged on the third transverse auxiliary wall 75 and the second operating part is arranged on the fourth transverse auxiliary wall 76 .

[0067] When manufacturing a wind turbine, the second working part is advantageously located in the auxiliary unit at an early stage of production, for example in a factory facility separate from the place where the wind turbine is assembled, referred to here as the first production location, where a number of auxiliary units are manufactured, for example in an assembly line.

[0068] The auxiliary unit can be transported to the site where the wind turbine will be installed, referred to here as the second manufacturing site. At this site, the first working part can be placed on the auxiliary unit. This procedure can be done on the ground before the nacelle is mounted on the tower or after the nacelle is mounted on the tower, and before the auxiliary unit is mounted on the main body or after the auxiliary unit is mounted on the main body.

[0069] FIG. 8 shows another assembly structure connecting the body frame and the operating components. In the illustrated embodiment, the assembly structure 80 connects the transformer 81 to the body frame. At the upper end of the assembly structure, a cross pin 82 can be suspended from the body frame, and at the lower end of the assembly structure, the assembly structure can be bolted to the body frame via holes 83. The assembly structure further includes a lower support structure 84, which can, for example, support the transformer on the floor of the nacelle until final assembly and attachment to the body frame. In particular, the transformer can be placed on the floor of the auxiliary unit and is bolted to the body frame when the auxiliary unit is attached to the body unit.

[0070] FIG. 9 shows an alternative assembly structure that includes pins 82, 90 that are suspended at both the upper and lower ends from the body frame.

[0071] FIG. 10 shows an alternative assembly structure in which both the upper and lower ends on one side include a bolt structure 100 that engages the body frame, and both the upper and lower ends on the other side of the assembly structure form hook structures 101 for suspending a working component.

[0072] Figure 11 shows diagrammatically that the main unit and the auxiliary units are separate units that are assembled before the nacelle is mounted on the tower or after the nacelle is mounted on the tower. Reference numbers also refer to the wind turbine of Figure 3.

[0073] Figures 12 to 15 show four different embodiments of the unit fixing structure forming the connection between the main unit and the auxiliary unit. In each of these four figures, the main unit 121 and the auxiliary unit 122 are connected by cooperating structures that form the unit fixing structure, which will be described in more detail below.

[0074] In FIG. 12, the cooperating structure is formed by a bracket 123 that joins the main unit and the auxiliary unit with bolts.

[0075] In Figure 13 the cooperating structure is constituted by a bottom bracket 123 similar to that used in Figure 12. At the top end the main unit and auxiliary unit are assembled by a hook 131 which is pivotally attached to the main unit at hinge point 132. The hook is rotatable as indicated by arrow 133 and when in the position shown engages an end bracket 134 on the auxiliary unit. Once the bottom bracket 123 has been removed and the hook 131 has been rotated into the main unit the auxiliary unit can be lowered to the ground.

[0076] The embodiment of Figure 14 is similar to that of Figure 13, but replaces the lower bracket with an upper bracket 141 and places the hook at the lower end.

[0077] In Figure 15, a lower bracket and an upper bracket are used to bolt the auxiliary unit to the main body, and with the bolts attached, the underside of the auxiliary unit is supported by a slidable support 151. If it is desired to lower the auxiliary unit to the ground, for example for replacement of working parts or maintenance, the slidable support can be slid to the left and the auxiliary unit can be lowered, for example using a crane built into the main unit.

[0078] In any of the embodiments shown in Figures 12-15, the brackets or hooks direct the load from the auxiliary unit to a rigid portion of the body unit, for example, a load-bearing post such as a post at a corner of the body unit. Various structural features can connect the brackets or hooks carrying the auxiliary unit directly to the body frame in the body unit to establish a load path to the tower. Thus, the auxiliary unit is indirectly connected to the tower through the body unit.

[0079] In addition to the hook and bracket unit fixing structure shown in Figures 12-15, assembly structures (e.g., shown in Figures 5, 6, 8, 9 and 10) connect operating components, such as a transformer, directly to the body frame within the body unit.

[0080] The main unit and the auxiliary unit may be joined together after the operating parts are disposed on the auxiliary unit, for example, after a transformer is disposed on the auxiliary unit. The operating parts may be disposed, for example, on the floor of the auxiliary unit, and it is desirable that the weight of the operating parts is mainly or completely borne by the main frame in the main unit when the auxiliary unit is fixed to the main unit.

[0081] During the assembly procedure, loads from the operating components are transferred to the auxiliary unit, for example from the floor of the auxiliary unit, to the main frame. This load transfer can occur while the auxiliary unit is attached to the main unit or after.

[0082] In one procedure, the working parts are gripped by the assembly structure while the auxiliary unit is lowered into a position where it is secured to the main unit. When the auxiliary unit reaches its assembled position, the load is transferred from the auxiliary unit to the main unit, and in particular to the main frame within the main unit.

[0083] In an alternative procedure, the auxiliary unit is lowered into a position where it is secured to the main unit. Thereafter, i.e., when the auxiliary unit reaches its assembled position, the load is transferred from the auxiliary unit to the main unit. This may include, for example, securing the working parts to the assembled structure and, optionally, removing or lowering the supports between the working parts and the floor of the auxiliary unit, thereby allowing the entire load to be transferred to the main frame.

[0084] In another alternative procedure, the auxiliary unit is held at an inclined angle to the horizontal while being lowered into position. When the first end of the auxiliary unit reaches the correct height, the first end is fixed to the main unit. The working part is placed on the second end opposite the auxiliary unit, and at the time when the first end is joined to the main unit, the working part is carried by the auxiliary unit, for example on the floor of the auxiliary unit. When the first end is fixed, the second end is lowered and the working part is gripped by the assembly structure. During the continued lowering of the second end, the weight of the working part is transferred from the auxiliary unit to the main frame, and finally, the second end of the auxiliary unit is attached to the main unit.

[0085] In another alternative procedure, the auxiliary unit is lowered to a position where it is secured to the main unit. During the lowering of the auxiliary unit, the working parts are gripped by the assembly structure and the lifting force from the crane is simultaneously adjusted to accommodate the changed balance when the working parts are gripped. Once the assembly position of the auxiliary unit is reached, the load is transferred from the auxiliary unit to the main unit and balance is maintained by dynamic adjustment of the lifting force, i.e., while the auxiliary unit is being lowered.

Claims

1. A wind turbine (1) comprising a tower (3), a nacelle (2) mounted on the tower (3) and a rotor for harvesting wind energy by rotation of the rotor about a rotor axis (7) extending in a vertical central plane (8), the nacelle comprising: a body unit (20) housing a rotor support assembly that defines a load path from the rotor to the tower; a first auxiliary unit (21) attached to the main unit on a first side of the central plane; a second auxiliary unit (22) attached to the main unit on a second side opposite to the first side with respect to the central plane; Including, The first and second auxiliary units each house a first and second operating part (34, 35); 1. A wind turbine, characterized in that first working parts of the first and second auxiliary units have the same distance to the central plane and second working parts of the first and second auxiliary units have different distances to the central plane.

2. 2. The wind turbine according to claim 1, characterized in that the first and second auxiliary units have substantially the same dimensions, the first working part being arranged in a mirror position with respect to the central plane and the second working part being arranged in substantially the same position within each auxiliary unit.

3. 2. The wind turbine of claim 1, wherein the first working component is mounted directly to the rotor support assembly and defines a load path from the first working component through the rotor support assembly to the tower.

4. 2. The wind turbine of claim 1, wherein the second working part is indirectly attached to the rotor support assembly via an auxiliary unit that houses the second working part, the indirect attachment defining a load path from the second working part through the auxiliary unit to the rotor support assembly and from the rotor support assembly to the tower.

5. The main unit rotates about a yaw axis (9) extending in a vertical transverse plane (10) perpendicular to the central plane (8), and the first working part rotates about the center of gravity (1 ｓｔ -COG) is attached to the rotor support assembly in a transverse plane or at a distance from the transverse plane that is less than the radial dimension (11, 12) of the tower.

6. The auxiliary unit has a center of gravity (AU-COG), and the distance from the rotor to the AU-COG is 1 ｓｔ - The wind turbine according to claim 1, characterized in that the distance is longer than the distance to the COG.

7. 2. Wind turbine according to claim 1, characterized in that both auxiliary units have first and second longitudinal auxiliary walls (70, 71) extending parallel to the centre plane between the first and second working parts, the first longitudinal auxiliary walls of both auxiliary units extending along an outer surface (72, 73) of the main unit, and the first working parts (35) of the first and second auxiliary units (21, 22) being arranged on the first longitudinal auxiliary wall.

8. 8. Wind turbine according to claim 7, characterized in that the first and second longitudinal auxiliary walls are joined by third and fourth transverse auxiliary walls (75, 76) extending perpendicularly to the centre plane (8) on either side of the first and second working parts, the third transverse auxiliary wall being closer to the rotor than the fourth transverse auxiliary wall, the first working part or the second working part being arranged at the same distance to the fourth transverse auxiliary wall.

9. 2. The wind turbine according to claim 1, wherein the first working part is heavier than the second working part.

10. 2. The wind turbine of claim 1, wherein the first and second working components are part of a power conversion assembly.

11. 11. The wind turbine of claim 10, wherein one of the first and second working components is a transformer, a converter, a battery, or a fuel cell.

12. Wind turbine according to claim 10, characterized in that the first working part is a transformer (35) and the second working part is a converter (34).

13. 2. The wind turbine according to claim 1, wherein the main unit includes first and second conductor structures in mirror positions with respect to the central plane and configured to connect the first and second working components to components within the main unit.

14. 14. The wind turbine according to claim 13, characterized in that the auxiliary units include auxiliary conductor structures having conductors (74) arranged to connect to one of the first and second conductor structures, the auxiliary conductor structures in the first auxiliary unit being different from the auxiliary conductor structures in the second auxiliary unit.

15. 2. The wind turbine according to claim 1, characterized in that each of the first and second auxiliary units comprises a connection structure having conductors for the electrical connection of the first working part, the connection structure comprising a conductor arrangement in a mirror position with respect to the central plane.

16. A method for manufacturing a wind turbine according to any one of claims 1 to 15, comprising the steps of: Assembling first and second auxiliary units at a first manufacturing site; mounting a second operative component within the first and second auxiliary units while the first and second auxiliary units are at the first manufacturing site; transporting the first and second auxiliary units to a second manufacturing site; inserting a first working component into the first and second auxiliary units while the first and second auxiliary units are at the second manufacturing site; Attaching a first working component to a rotor support assembly; The method according to claim 1, further comprising:

17. 17. The method of claim 16, wherein the second manufacturing site is where the nacelle is attached to the tower.

18. 20. The method of claim 17, wherein the first working part is inserted into the first and second auxiliary units after the nacelle is mounted to the tower.

19. 17. The method of claim 16, wherein the step of inserting the first operating part into the first and second auxiliary units occurs after the step of attaching the first and second auxiliary units to the main unit.

20. 17. The method of claim 16, wherein the step of inserting the first operating part into the first and second auxiliary units occurs before the step of attaching the first and second auxiliary units to the main unit.

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